Relocation of the hypocenter using the double-difference method around Weber Deep Banda

Abstract

There were conducted 1002 hypocenter relocations out of 1014 earthquake events were based on 33 earthquake recording stations used. Based on the results of the histogram of the residual time close to zero, this indicates that the Double Difference method is relatively accurate for relocating earthquakes in the Weber Deep Banda in 2008-2019. The cross-section (A-B) shows seismic activity following the shape of a slab that slopes gently from east to west. Seismic activity occurs at a depth of 0 to 200 km with the dominance of medium and shallow earthquakes and has a shear fault mechanism pattern. In the cross-section (C–D) of the Weber Deep region, shallow crust earthquake activity is very rare and is dominated by medium earthquakes in the Benioff-Wadati zone in the central and western parts of the Weber Deep. The results of the relocation show that there is a seismic gap from the slab that is subducting from the east to the southeast. Seismic activity is concentrated vertically in the center (circular pattern) at a depth of 90 to 140 km and generally has a shear fault mechanism. Earthquake activity in the cross-section (E–F) is dominated by medium earthquakes in the Benioff-Wadati zone on the south side of the Weber Deep. The results of the relocation show that there is a seismic gap from the slab that subducts from the east in the western part of the weber deep and then moves diagonally to the southeast at a depth of 100 to 200 km and has a shear fault mechanism.